Arie Bregman

Linux And Stuff

Month: February 2017

TripleO: Debugging Overcloud Deployment Failure

You run ‘openstack overcloud deploy’ and after a couple of minutes you find out it failed and if that’s not enough, then you open the deployment log just to find a very (very!) long output that doesn’t give you an clue as to why the deployment failed. In the following sections we’ll see how can we get to the root of the problem.

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Python: check if two strings are permutations of each other

Another question I cover in a presentation I’m preparing for “Open University meets Open Source” meetups.

What is a Permutation?

Permutation is the action of rearranging objects, characters or symbols into different, unique sequences.

Each sequence is called ‘permutation’.

It’s common to see people mix permutation with combination, but those are two different things. Remember, combination doesn’t care about the order, while permutation does.

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Python: check if one string is a rotation of another string

Another question I cover in a presentation I’m preparing for “Open University meets Open Source” meetups.

The question

You have two strings, str1 and str2 and you need to return True if the first string is a rotation of the second string. Otherwise, return False.

Examples

“hello”,    “llohe” -> True. If we’ll rotate the second string twice, you’ll get ‘hello’.

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